Seperation-Problem of phenol and o-cresol

[Roehrs]

Hello,

I have a problem to seperate cresol from phenol. They always come at the same time while the boiling points differ in 10°C. Has anyone an Idea to solve the problem?

I`m analysing them by GC/FID and splitless injection mode with a HP-INNOWax (PEG) column. I`m using toluene as solvent, diethylbenzene as standard and following temperature program:

40°C(2min)-10°C/min-140°C-1°C/min-170°C-4°C/min-220°C-10°C/min-250°C

Thanks
Oliver

[chromatographer1]

Boiling point is not the only mechanism of separation with the Wax column.

If you can use a silicone column (5% Phenyl or Vocol) and derivatize the phenol and cresol to its trimethyl silyl ether (BSA) you should have no problem in separating the two.

Otherwise I would try a glass packed column with a Carbopack B support coated with Carbowax 20M.

I would recommend a call to Supelco technical support. 800-359-3041

best wishes,

Rod

[gcguy]

I have just set up a seperation for o-cresol and phenol.
HP1 30m x 0.32mm x 0.25um H2 carrier at 2.5ml/min. 50C(0min) 40C/min to 250C.phenol rt 2.5min, ocresol 2.7min. I have used an on column injection for this but I am sure it will still work on splitless.
propan-2-ol for the sample prep.

Hope this helps.

GCguy